Synthesis of Cardiotonic Steroids Oleandrigenin and Rhodexin B

J Org Chem. 2021 Aug 6;86(15):10249-10262. doi: 10.1021/acs.joc.1c00985. Epub 2021 Jul 13.

Abstract

This article describes a concise synthesis of cardiotonic steroids oleandrigenin (7) and its subsequent elaboration into the natural product rhodexin B (2) from the readily available intermediate (8) that could be derived from the commercially available steroids testosterone or DHEA via three-step sequences. These studies feature an expedient installation of the β16-oxidation based on β14-hydroxyl-directed epoxidation and subsequent epoxide rearrangement. The following singlet oxygen oxidation of the C17 furan moiety provides access to oleandrigenin (7) in 12 steps (LLS) and a 3.1% overall yield from 8. The synthetic oleandrigenin (7) was successfully glycosylated with l-rhamnopyranoside-based donor 28 using a Pd(II)-catalyst, and the subsequent deprotection under acidic conditions provided cytotoxic natural product rhodexin B (2) in a 66% yield (two steps).

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Antineoplastic Agents*
  • Cardenolides
  • Cardiac Glycosides*
  • Oxidation-Reduction

Substances

  • Antineoplastic Agents
  • Cardenolides
  • Cardiac Glycosides
  • oleandrigenin